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Utility of cell salvage in women undergoing abdominal myomectomy
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GENERAL GYNECOLOGY
Utility of cell salvage in women undergoing abdominal myomectomy Moeun Son, MD; John C. Evanko, MD; Linda B. Mongero, CCP; Sharyn N. Lewin, MD; Yu-Shiang Lu, MS; Thomas J. Herzog, MD; Jin Hee Kim, MD; Jason D. Wright, MD OBJECTIVE: We examined the use and cost of autologous blood cell salvage in women who undergo abdominal myomectomy. STUDY DESIGN: Patients who underwent abdominal myomectomy
from 2007-2011 were identified. Use of the cell salvage system and reinfusion of autologous blood in women who had the system set-up were analyzed. Cost was examined by directly reported data. RESULTS: We identified 607 patients who underwent abdominal
myomectomy. Four hundred twenty-five women (70%) had the set-up of the cell salvage system. Cell-salvaged blood was processed and reinfused into 85 of these subjects (20%). In a multivariable model, performance of myomectomy by a gynecologic-specific surgeon (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.28e3.59), >5 myomas (OR, 2.49; 95% CI, 1.27e4.89), and larger uterine size statistically were associated significantly with cell-salvage device set-up. Conversely, having a reproductive-endocrinology-infertility specialist
as the surgeon was associated with a significant reduction in cellsalvage system set-up (OR, 0.37; 95% CI, 0.21e0.66). For the women who had cell-salvage system set-up, uterine size of >15-19 weeks of gestation (OR, 3.22; 95% CI, 1.56e8.95) or 20 weeks of gestation (OR, 4.62; 95% CI, 1.45e14.73), operating time of >120 minutes (OR, 3.98; 95% CI, 1.70e9.29), and intraoperative blood loss of >1000 mL (OR, 26.31; 95% CI, 10.49e65.99) were associated significantly with a higher incidence of reinfusion of cell-salvaged blood. CONCLUSION: The routine use of cell salvage in women who undergo
abdominal myomectomy does not appear to be warranted. Cellsalvage set-up appears to be cost-effective only when reinfused, but clinical characteristics cannot predict accurately which women will require reinfusion of cell-salvaged blood. Key words: blood, cell saver, transfusion
Cite this article as: Son M, Evanko JC, Mongero LB, et al. Utility of cell salvage in women undergoing abdominal myomectomy. Am J Obstet Gynecol 2014;210:.
A
bdominal myomectomy is performed commonly for the excision of symptomatic uterine fibroid tumors in women who desire fertility preservation. Although an effective treatment, the procedure can be associated with substantial blood loss.1,2 A number of adjuvant measures are available to reduce the risk of bleeding that include preoperative administration of gonadotropinreleasing hormone agonists, placement of a pericervical tourniquet, injection of intramyometrial vasopressin, and use of
uterotonics.3-7 Despite these measures, allogeneic transfusion is often required, with reported rates between 18% and 24% in some studies.8-10 Although allogeneic red blood cell transfusion is effective in the treatment of anemia because of acute blood loss, transfusion is associated with a number of risks that include infectious complications, transfusion reactions, and a substantial cost. To limit allogeneic transfusion, cell salvage and autologous blood recovery have been developed for
From the Department of Obstetrics and Gynecology (Drs Son, Evanko, Lewin, Herzog, Kim, and Wright and Ms Lu) and Herbert Irving Comprehensive Cancer Center (Drs Lewin, Herzog, and Wright), College of Physicians and Surgeons, and Department of Clinical Perfusion, New York Presbyterian Hospital, Columbia University Medical Center (Ms Mongero), Columbia University, New York, NY. Received Nov. 25, 2013; revised Jan. 30, 2014; accepted Feb. 15, 2014. The authors report no conflict of interest. Reprints: Jason D. Wright, MD, Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, 161 Fort Washington Ave., 8th Floor, New York, NY 10032. [email protected]. 0002-9378/$36.00 ª 2014 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog.2014.02.020
procedures in which substantial blood loss is anticipated. Cell salvage has been studied for orthopedic and cardiovascular procedures, and the technology has been associated with decreased need for allogeneic blood transfusion and fewer bleeding complications.11-16 Despite the bleeding potential of myomectomy, there have been few data to describe the role of cell salvage for the procedure. Small observational studies have suggested that cell salvage may increase the postoperative hematocrit level and reduce the need for allogeneic transfusion.17-19 However, the sample size in these studies was small, and the cell-salvage system often was evaluated within a subgroup analysis and not the main focus of the studies. Furthermore, little is known about the cost-effectiveness of cell salvage for myomectomy. The primary objective of our study was to examine the usefulness of cell salvage in women who undergo abdominal myomectomy. We also investigated factors that were associated with rates of cell-salvage set-up and reinfusion and
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used these data to help estimate costs of this technology.
M ATERIALS
AND
M ETHODS
Data for women who underwent abdominal myomectomy between January 2007 and December 2011 were analyzed. A consecutive list of patients who underwent myomectomy was identified with the use of institutional databases. Patients who underwent minimally invasive, hysteroscopic, or vaginal myomectomy were excluded from the analysis, given the relatively low number of cases during the study time period. Study approval was obtained from the Columbia University Institutional Review Board. Medical records were reviewed, and relevant data were extracted. Data that were obtained included patient demographic information (age at time of surgery, race, parity), specialty of the attending surgeon, indication for surgery, preoperative imaging and laboratory data, uterine size on physical examination, total operating time, and estimated blood loss. The indication for surgery was classified based on the patient’s chief complaint. Preoperative anemia was defined as a hematocrit level of <35%. Uterine size was based on “weeks of gestation” because it is measured routinely on physical examination. Each patient was classified as to whether the cell-salvage system was set-up in the operating room before the initiation of the myomectomy. All patients who had cell-salvage use had the BRAT 2 device (COBE, Arvada, CO). This device suctions blood from the operative field, mixes it with heparinized saline solution, and stores the blood in a canister. When enough blood has been accumulated, the blood is processed by centrifugation and filtration, mixed with saline solution, and reinfused into the patient. The primary outcome for this study was the set-up of the cell-salvage device during abdominal myomectomy. The secondary outcome was incidence of reinfusion of cell-salvaged blood. We analyzed factors that potentially could be associated with cell-salvage set-up and reinfusion. We also estimated the cost of cell-salvage set-up and reinfusion
in comparison to allogeneic blood transfusion. The estimated cost of allogeneic blood transfusion was determined by the presence of a the current procedural terminology code that corresponded with each step of the blood transfusion process, including ABO (86900), Rh (86901), antibody screen (86850), immediate spin cross-match (86920), incubation technique (86921), and blood administration (36430).20 These current procedural terminology codes were then cross-referenced to Medicare reimbursement payments with the use of the website www.cms.gov. The estimated cost of the cell-salvage system was determined by the New York Presbyterian Hospital Division of Clinical Perfusion by estimation of the cost of the CellSaver (Haemonetrics, Braintree, MA) machine and supplies in addition to cost of a perfusionist’s time (both set-up/pack-up time and operating time) per hour. These estimates were used to calculate the total costs of the blood products that were used in the abdominal myomectomies that we analyzed. We performed several sensitivity analyses and estimated the total costs under a variety of clinical scenarios. Clinical scenarios included whether all of the patients who underwent abdominal myomectomy in our study had had cell-salvage device set-up, whether none of the patients had cellsalvage set-up, whether set-up was done only for those we knew were going to require reinfusion of salvaged blood, and whether only the patients we had identified as “high risk” based on our predictive indicators had cell-salvage set-up. Frequency distributions based on setup of the cell-salvage device and reinfusion of cell-salvaged blood were analyzed with c2 tests. For the analysis of reinfusion of cell-salvaged blood, we included only patients who had the cell-salvage device set-up. Multivariable logistic regression models were constructed to examine predictors of cell-salvage set-up and reinfusion of cell-salvaged blood, and adjustments were made for other demographic and clinical variables. A second predictive model for reinfusion of cell-salvaged blood that included only variables that were available before
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www.AJOG.org surgery is also reported. Results are reported as odds ratios (ORs) with 95% confidence intervals (CIs). All statistical tests were 2-sided; a probability value of < .05 was considered statistically significant. SAS software (version 9.3; SAS Institute Inc, Cary, NC) was used for all statistical analyses.
R ESULTS A total of 607 patients who underwent abdominal myomectomy were identified. In this sample, 425 patients (70.0%) had the cell salvage machine set-up for collection; 182 women (30.0%) did not. The rates of cell-salvage set-up between 2007 and 2011, per quarter, are presented in Figure 1. The procedures were performed by 46 surgeons, with a median operative volume of 6 cases (range, 1e94). The rate of cell-salvage set-up by quarter ranged from 46.4e87.8%. The clinical characteristics of the cohort are displayed in Table 1. No difference was observed between the patients who had cell-salvage system set-up and those who did not have the set-up with regard to age, race, year of surgery, or performance of previous myomectomy (P > .05 for all). Bleeding as an indication for surgery (P ¼ .01), lower preoperative hematocrit level (P ¼ .01), performance of myomectomy by a gynecologic-specific surgeon (P <.0001), uterine size >15 weeks of gestation on physical examination (P < .0001), and >5 fibroid tumors visualized on preoperative imaging (P < .0001) were associated significantly with higher incidence of cell-salvage set-up. In the adjusted model, performance of myomectomy by a gynecologic-specific surgeon (OR, 2.14; 95% CI, 1.28e3.59), >5 myomas (OR, 2.49; 95% CI, 1.27e4.89), and larger uterine size statistically were associated significantly with cell-salvage set-up (Table 1). Conversely, having a reproductive-endocrinology-infertility specialist as the surgeon was associated with a significant reduction in cellsalvage device set-up (OR, 0.37; 95% CI, 0.21e0.66). A total of 144 units of salvaged blood were processed and reinfused into 85 patients (20.0%). There were no intra-or postoperative complications that were
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FIGURE 1
Cell-salvage device set-up
Rates of cell-salvage device set-up during abdominal myomectomy from 2007-2011 stratified by year and quarter. Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
associated with reinfusion of cellsalvaged blood. The rates of reinfusion of cell-salvaged blood between 2007 and 2011, per quarter, are presented in Figure 2. The women who had cell-salvage device set-up were then stratified based on whether they were reinfused, and these 2 subgroups were then compared (Table 2). Age, race, year of surgery, surgeon specialty, previous myomectomy, indication, preoperative hematocrit level, and number of fibroid tumors were not associated with reinfusion of cell-salvaged blood. Uterine size >15-19 weeks of gestation (OR, 3.22; 95% CI, 1.56e8.95) or 20 weeks of gestation (OR, 4.62; 95% CI, 1.45e14.73), operating time >120 minutes (OR, 3.98; 95% CI, 1.70e9.29), and intraoperative blood loss >1000 mL (OR, 26.31; 95% CI, 10.49e65.99) were associated significantly with a higher incidence of reinfusion of cell-salvaged blood. A predictive model that included only variables that were available before the operation and excluded operative time and blood loss revealed similar findings. Allogeneic red blood cell transfusion was also used in some patients during and after abdominal myomectomy. Allogeneic blood was transfused during surgery in 15 patients (2.5%). Three of
these patients had not had cell-salvage device set-up at the time of surgery; these patients received a total of 6 units of allogeneic packed red blood cells intraoperatively. Among the 12 patients who also had cell-salvage device set-up, they received 38 units of cell-salvaged blood and 41 units of allogeneic blood during surgery. Allogeneic blood was transfused after surgery in 41 patients (6.8%). Ten of these patients did not have cell-salvage device set-up at time of surgery; these patients received a total of 20 units of allogeneic packed red blood cells. Among the 31 patients who had also had cell-salvage device set-up in the operating room, they received 49 units of cell-salvaged blood during surgery and an additional 66 units of allogeneic blood after surgery. Of note, 6 of these patients experienced postoperative bleeding complications. Two of them required reoperation: 1 woman for hemoperitoneum and the other woman for incisional bleeding. The estimated total cost in our study, which included the cost of the cellsalvage system set-up in the 425 patients and the cost of the allogeneic blood units that were still necessary was $146,587. The estimated total costs for a variety of clinical scenarios are displayed in Table 3. The hypothesized cost for a
Research
clinical scenario in which the cell-salvage device was set up in all patients was calculated with the cost of the cellsalvage system set-up in all 607 patients and the reduced cost of the allogeneic blood units that were still required (as a crude estimate, we subtracted the 26 units of allogeneic blood that were transfused in the nonecell-salvage device set-up group in our study). Universal cell-salvage device set-up was associated with a cost of $179,819 ($33,232 more than the actual cohort). In the scenario of not setting up the cell-salvage machine in any cases, the cost was determined by conversion of the cost of each unit of reinfused cellsalvaged blood to the price of a unit of allogeneic blood, which resulted in $91,410 ($55,177 less than the actual cohort). In the ideal scenario of setting up the cell-salvage machine only in cases in which reinfusion was achieved, the estimated cost included the cost of the cell-salvage system set-up in the 85 patients who were ultimately reinfused and the cost of the allogeneic blood units that were still necessary and resulted in $67,853 ($78,734 less than the actual cohort). Finally, we hypothesized a scenario in which only the patients that we had identified as “high risk” for significant blood loss based on our multivariable analysis had had cell-salvage machine set-up; using these results, we noted a cost of $120,714 ($25,873 less than the actual cohort).
C OMMENT In an attempt to avoid allogeneic blood transfusion during the perioperative period, advances such as cell salvage have been used in gynecologic surgery without strong data to describe the effectiveness of these technologies. Although it is reassuring to have an autologous blood recovery system set-up for the possibility of significant operative blood loss, it is also associated with substantial cost. Our data demonstrated that, although the cell-salvage system may be beneficial in certain situations, its routine use in patients who undergo abdominal myomectomy might not be warranted.
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TABLE 1
Clinical and demographic characteristics stratified by set up of cellsalvage Variable
Cell-salvage No cell salvage, device set-up, n (%) n (%)
Total
425 (70.0)
Odds ratio P valuea (95% CI)b
182 (30.0)
Age at time of surgery, y
— .55
<35
123 (28.9)
57 (31.3)
Referent
35-40
193 (45.4)
74 (40.7)
1.53 (0.96e2.45)
>40
109 (25.7)
51 (28.0)
1.16 (0.69e1.96)
Race
.24
White
117 (27.5)
56 (30.7)
Referent
Black
172 (40.5)
58 (31.9)
1.34 (0.81e2.22)
Other
60 (14.1)
32 (17.6)
0.78 (0.42e1.45)
Unknown
76 (17.9)
36 (19.8)
0.86 (0.48e1.54)
2007
113 (26.6)
41 (22.5)
Referent
2008
98 (23.1)
31 (17.1)
1.15 (0.62e2.13)
2009
87 (20.5)
39 (21.4)
0.70 (0.40e1.25)
2010
62 (14.6)
43 (23.6)
0.41 (0.22e0.76)
2011
65 (15.2)
28 (15.4)
0.54 (0.28e1.03)
Year of surgery
.06
< .0001
Specialty of surgeon General obstetrics/gynecology
144 (33.9)
59 (32.4)
Referent
Gynecologic surgery
185 (43.5)
39 (21.4)
2.14 (1.28e3.59)
Gynecology oncology
12 (2.8)
11 (6.1)
0.37 (0.13e1.03)
Reproductiveendocrinology-infertility
84 (19.8)
73 (40.1)
0.37 (0.21e0.66)
Previous myomectomy
.07
No
383 (90.1)
172 (94.5)
Yes
42 (9.9)
10 (5.5)
Indication for surgery Abnormal vaginal bleeding Bulk symptoms Pelvic pain Infertility
Referent 1.82 (0.81e4.06) .01
216 (50.8)
67 (36.8)
Referent
42 (9.9)
19 (10.4)
0.60 (0.29e1.22)
102 (24.0)
58 (31.9)
0.54 (0.33e0.87)
65 (15.3)
38 (20.9)
1.01 (0.55e1.87)
Fibroid tumors on imaging, n
.0004
1-5
216 (50.8)
99 (54.4)
Referent
>5
89 (21.0)
15 (8.2)
2.49 (1.27e4.89)
120 (28.2)
68 (37.4)
0.98 (0.61e1.58)
Unknown
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
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(continued)
Cell-salvage technology has now been well-described for a number of nongynecologic procedures.11 A systematic review by Carless et al11 showed that cell salvage reduces the need for transfusions of allogeneic blood in orthopedic, cardiac, and vascular surgery. In their metaanalysis of 75 trials, they found that the use of cell salvage reduced the rate of exposure to allogeneic red blood cell transfusion by 38%. The absolute reduction in risk of receiving an allogeneic red blood cell transfusion was 21%; the use of cell salvage resulted in an average savings of 0.68 units of allogeneic red blood cells per patient (weighted mean difference, e0.68; 95% CI, e0.88 to e0.49). Earlier studies have suggested that cell salvage may be beneficial in women who undergo myomectomy.17-19 Yamada at al17 reported that the use of intraoperative cell salvage allowed surgeons to avoid allogeneic transfusion in 35 of 37 patients, which included 4 patients who had an estimated operative blood loss of >1000 mL. West et al18 found that, among 90 women, 70 women were given cell-salvaged blood (mean, 355 mL) and that allogeneic blood transfusion was necessary for only 7 women (8%). At our institution, cell-salvage technology was used liberally in women who underwent myomectomy, and we noted that autologous blood infrequently was reinfused; only 20% of those who had cell-salvage device set-up received reinfusion. Further, despite the frequent use of cell salvage, 107 additional units of allogeneic blood were still required by the cohort. The strength of this study lies in the abundance of information on confounding factors that allowed us to analyze specific variables that were associated with increased rates of set-up and use of the cell-salvage system in an effort to determine predictive clinical indicators that would be helpful before surgery. We found that, having a gynecology-specific surgeon, uterine size >15 weeks of gestation on physical examination, and >5 fibroid tumors that were seen on imaging were associated with higher rates of set-up of the cellsalvage system. However, when we
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TABLE 1
Clinical and demographic characteristics stratified by set up of cellsalvage (continued) Variable
Cell-salvage No cell device salvage, set-up, n (%) n (%)
< .0001
Uterine size on exam, wk <15
149 (35.0)
15-19 20 Unknown
91 (50.0)
Referent
130 (30.6)
34 (18.7)
2.17 (1.30e3.63)
84 (19.8)
18 (9.9)
3.27 (1.71e6.23)
62 (14.6)
39 (21.4)
1.57 (0.91e2.72)
Preoperative hematocrit level, %
a
Odds ratio P valuea (95% CI)b
.01
25-29
20 (4.7)
5 (2.8)
Referent
30-34
116 (27.3)
29 (15.9)
1.24 (0.39e3.93)
34-39
203 (47.8)
104 (57.1)
0.57 (0.19e1.72)
40
86 (20.2)
44 (24.2)
0.55 (0.17e1.77)
c2 test; b Derived from multivariable logistic regression model.
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
focused on the patients who actually received reinfusion of cell-salvaged blood, the only variable that was statistically significant and available before surgery was uterine size >15 weeks of gestation on physical examination. This association may underlie the high rates of reinfusion of cell-salvaged blood in
the study by West et al18 because only women with uterine size 16 weeks of gestation were included. Based on our data, there are few other predictive factors to help guide selective cell-salvage device set-up policies. Cell salvage is cost-effective for procedures in which the need for allogeneic
FIGURE 2
Cell-salvage reinfusion
Rates of cell salvage reinfusion during abdominal myomectomy from 2007-2011 stratified by year and quarter. Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
Research
blood transfusion is high.21 Although the cost (per unit of blood) is appreciably less for cell-salvaged blood compared with allogeneic transfusion, the overall cost-effectiveness of the cell-salvage system is dependent on the rates of reinfusion. Additionally, even if cell-salvaged blood is frequently reinfused, there can still be a need for additional allogeneic blood products. Compared with other higher risk procedures, we noted that the number of women who had cell-salvaged blood reinfused was low. Not unexpectedly, in our comparison of costs in different clinical scenarios, the estimated cost was highest for the situation in which every patient who underwent abdominal myomectomy had cell-salvage device set-up. Likewise, the estimated cost was the lowest in the ideal scenario in which we could predict accurately which patients were going to definitely receive reinfusion, and the cell-salvage device was set-up only in those patients. Use of a model to predict “high-risk” patients resulted in marginal cost-savings. These models did not account for adverse consequences of allogeneic transfusion, and clearly additional econometric studies are needed. However, our data suggest that a riskbased stratification for cell-salvage device set-up is unlikely to reduce the cost of using the technology substantially. Although our study is one of the largest to date to describe the use of the cell-salvage system for abdominal myomectomy, we acknowledge a number of important limitations. First, the study design is retrospective in nature; as such, the decision to set-up the cell-salvage system was at the discretion of the attending surgeon. However, selection bias towards using the cell-salvage system in higher risk patients likely biased our findings towards the usefulness of cell salvage, and the utility of cell salvage would have been even more limited if all women had the system set-up. Second, there are no set criteria as to when cellsalvaged blood should be reinfused. Although blood is often reinfused if enough blood cells are collected, undoubtedly a number of women received autologous blood that was of little clinical value. An abundance of literature
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TABLE 2
Characteristics of the women with reinfusion of cell-salvaged blood Variable
Reinfused, n (%)
Not reinfused, n (%)
Total
85 (20.0)
340 (80.0)
Age at time of surgery, y
P valuea
Odds ratio (95% CI)b
Predictive model odds ratio (95% CI)c
— .60
<35
28 (32.9)
95 (27.9)
35-40
35 (41.2)
158 (46.5)
0.48 (0.20e1.13)
0.60 (0.30e1.20)
>40
22 (25.9)
87 (25.6)
0.49 (0.19e1.28)
0.71 (0.33e1.55)
Race
Referent
Referent
.08
White
17 (20.0)
100 (29.4)
Black
43 (50.6)
129 (37.9)
0.70 (0.28e1.79)
1.80 (0.84e3.85)
Other
8 (9.4)
52 (15.3)
0.29 (0.06e1.28)
0.56 (0.19e1.71)
17 (20.0)
59 (17.4)
0.95 (0.32e2.86)
1.72 (0.70e4.20)
Unknown Year of surgery
Referent
Referent
.01
2007
30 (35.3)
83 (24.5)
2008
16 (18.8)
82 (24.1)
Referent 0.60 (0.21e1.67)
Referent 0.50 (0.22e1.14)
2009
8 (9.4)
79 (23.2)
0.18 (0.05e0.66)
0.22 (0.08e0.56)
2010
17 (20.0)
45 (13.2)
0.93 (0.31e2.74)
1.15 (0.49e2.71)
2011
14 (16.5)
51 (15.0)
0.75 (0.25e2.29)
0.57 (0.23e1.40)
Specialty of surgeon
.001
General obstetrics/gynecology
34 (40.0)
110 (32.4)
Gynecologic surgery
22 (25.9)
163 (47.9)
Gynecology oncology
Referent
Referent
0.47 (0.19e1.17)
0.34 (0.17e0.71)
5 (5.9)
7 (2.1)
2.81 (0.50e15.66)
1.21 (0.29e5.09)
24 (28.2)
60 (17.6)
1.25 (0.40e3.93)
1.33 (0.56e3.17)
No
68 (80.0)
315 (92.6)
Yes
17 (20.0)
25 (7.4)
Reproductive-endocrinology-infertility Previous myomectomy
.0005
Indication for surgery
Referent 1.51 (0.54e4.25)
Referent 2.82 (1.24e6.40)
.50
Abnormal vaginal bleeding
43 (50.6)
173 (50.9)
Bulk symptoms
12 (14.1)
30 (8.8)
2.12 (0.69e6.49)
1.27 (0.51e3.15)
Pelvic pain
18 (21.2)
84 (24.7)
0.81 (0.32e2.04)
0.72 (0.35e1.48)
Infertility
12 (14.1)
53 (15.6)
0.60 (0.19e1.87)
0.57 (0.23e1.44)
Fibroid tumors on imaging, n
Referent
Referent
.18
1-5
36 (42.4)
180 (52.9)
>5
19 (22.3)
70 (20.6)
Referent 1.02 (0.38e2.77)
Referent 1.27 (0.58e2.78)
Unknown
30 (35.3)
90 (26.5)
1.34 (0.53e3.38)
1.71 (0.84e3.57)
< .0001
Uterine size on examination, wk <15
8 (9.4)
141 (41.5)
15-19
27 (31.8)
103 (30.3)
Referent
Referent
3.22 (1.56e8.95)
4.71 (1.94e11.43)
20
37 (43.5)
47 (13.8)
4.62 (1.45e14.73)
15.48 (6.07e39.48)
Unknown
13 (15.3)
49 (14.4)
1.97 (0.55e7.00)
3.81 (1.34e10.83)
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TABLE 2
Characteristics of the women with reinfusion of cell-salvaged blood (continued) Reinfused, n (%)
Variable
Not reinfused, n (%)
P valuea
Preoperative hematocrit level, %
Predictive model odds ratio (95% CI)c
Referent
Referent
.07
25-29
6 (7.0)
14 (4.1)
30-34
26 (30.6)
90 (26.5)
1.21 (0.23e6.29)
0.88 (0.25e3.08)
35-39
44 (51.8)
159 (46.8)
1.22 (0.25e5.97)
0.72 (0.22e2.35)
40
9 (10.6)
77 (22.6)
0.70 (0.11e4.51)
0.52 (0.13e2.13)
< .0001
Operating time, min <120
13 (15.3)
197 (57.9)
120
72 (84.7)
143 (42.1)
Referent
—
3.98 (1.70e9.29)
—
< .001
Intraoperative blood loss, mL
a
Odds ratio (95% CI)b
<1000
33 (38.8)
331 (97.4)
1000
52 (61.2)
9 (2.6)
Referent
—
26.31 (10.49e65.99)
—
c test; Derived from multivariable logistic regression model; Multivariable logistic regression model including only factors available before surgery. 2
b
c
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
supports the fact the young women often tolerate mild anemia well. Third, we were unable to incorporate data such as patient body mass index and medical comorbidities or surgeon level of experience and surgical volume, which
potentially could be important confounding factors. Finally, we acknowledge that our cost models are unable to incorporate a number of factors that impact cost. A priori, the goal of the cost analysis was to report descriptively the
estimated costs of cell salvage in our cohort. However, institutional costs of the technology are likely highly variable, and our model did not incorporate costs of acute and long-term complications of allogeneic transfusion, such as
TABLE 3
Cost estimates for use of cell salvage for myomectomy Cell salvage system Total cost of set-up
Total cost of perfusionist
Allogeneic blood transfusion
Setting
Cost per Cost per Red blood Cost per Total estimated Set-up, n set up, $ Time, h hour, $ Subtotal,a $ cell units, n unit,b $ Subtotal, $ cost, $
Our study results
425
125
918
54
102,697
133
330
43,890
146,587
330
35,310
179,819
133 (144d) 330
91,410
91,410
c
If all cases had cell-salvage 607 device set-up
125
1271
54
144,509
If no cases had cell-salvage — device set-up
—
—
—
—
If cell-salvage device set-up only for those who were ultimately reinfused
85
125
247
54
23,963
133
330
43,890
67,853
If cell-salvage device set-up 266 only for high-risk patients
125
756
54
76,824
133
330
43,890
120,714
a
107
Subtotal cost of cell-salvage system as determined by division of clinical perfusion by estimating the cost of the CellSaver (Haemonetrics, Braintree, MA) machine and supplies in addition to the cost of a perfusionist’s time per hour of operating time; b Determined by the presence of a current procedural terminology code that corresponded with each step of the blood transfusion process, including ABO (86900), Rh (86901), antibody screen (86850), immediate spin cross-match (86920), incubation technique (86921), blood administration (36430); c Total number of allogeneic blood units still needed, even with cell-salvage device set-up in our study; d Total number of blood units provided by the cell-salvage machine when used in our study.
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
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transfusion reactions and acquired blood-borne infections. In conclusion, we found that the routine use of cell-salvage technology was not beneficial in most women who undergo abdominal myomectomy. Reinfusion rates were low; allogeneic blood transfusions were often still necessary, and costs were increased. However, women with uterine size >15 weeks of gestation on physical examination were found to have significantly increased rates of reinfusion of cell-salvaged autologous blood. Further studies are needed to better elucidate other significant risk factors and to identify women who would benefit from cell-salvage technology. REFERENCES 1. Kunde K, Cortes E, Seed P, Khalaf Y. Evaluation of perioperative morbidity associated with single and multiple myomectomy. J Obstet Gynaecol 2009;29:737-41. 2. Pundir J, Krishnan N, Siozos A, et al. Perioperative morbidity associated with abdominal myomectomy for very large fibroid uteri. Eur J Obstet Gynecol Reprod Biol 2013;167:219-24. 3. Lethaby A, Vollenhoven B, Sowter M. Efficacy of pre-operative gonadotropin hormone releasing analogues for women with uterine fibroids undergoing hysterectomy or myomectomy: a systematic review. BJOG 2002;109: 1097-108. 4. Al-Shabibi N, Chapman L, Madari S, Papadimitriou A, Papalampros P, Magos A.
Prospective randomised trial comparing gonadotrophin-releasing hormone analogues with triple tourniquets at open myomectomy. BJOG 2009;116:681-7. 5. Kongnyuy EJ, van den Broek N, Wiysonge CS. A systematic review of randomized controlled trials to reduce hemorrhage during myomectomy for uterine fibroids. Int J Gynaecol Obstet 2008;100:4-9. 6. Celik H, Sapmaz E. Use of a single preoperative dose of misoprostol is efficacious for patients who undergo abdominal myomectomy. Fertil Steril 2003;79:1207-10. 7. Agostini A, Ronda I, Franchi F, et al. Oxytocin during myomectomy: a randomized study. Eur J Obstet Gynecol Reprod Biol 2005;118:235-8. 8. Berkeley AS, DeCherney AH, Polan ML. Abdominal myomectomy and subsequent fertility. Surg Gynecol Obstet 1983;156:319-22. 9. Ginsburg ES, Benson CB, Garfield JM, Gleason RE, Friedman AJ. The effect of operative technique and uterine size on blood loss during myomectomy: a prospective randomized study. Fertil Steril 1993;60:956-62. 10. Gehlbach DL, Sousa RC, Carpenter SE, Rock JA. Abdominal myomectomy in the treatment of infertility. Int J Gynaecol Obstet 1993;40: 45-50. 11. Carless PA, Henry DA, Moxey AJ, O’Connell D, Brown T, Fergusson DA. Cell salvage for minimising perioperative allogeneic blood transfusion. Cochrane Database Syst Rev 2010;3:CD001888. 12. Vonk ABA, Meesters MI, Garnier RP, et al. Intraoperative cell salvage is associated with reduced postoperative blood loss and transfusion requirement in cardiac surgery: a cohort study. Transfusion 2013;53:2782-9. 13. Weltert L, Nardella S, Rondinelli MB, Pierelli L, De Paulis R. Reduction of allogeneic
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www.AJOG.org red blood cell usage during cardiac surgery by an integrated intra- and postoperative blood salvage strategy: results of a randomized comparison. Transfusion 2013;53:790-7. 14. Moonen AF, Knoors NT, van Os JJ, Verburg AD, Pilot P. Retransfusion of filtered shed blood in primary total hip and knee arthroplasty: a prospective randomized clinical trial. Transfusion 2007;47:379-84. 15. Gannon DM, Lombardi AV Jr, Mallory TH, Vaughn BK, Finney CR, Niemcryk S. An evaluation of the eficacy of postoperative blood salvage after total joint arthroplasty. a prospective randomized trial. J Arthroplasty 1991;6: 109-14. 16. Ashworth A, Klein AA. Cell salvage as part of a blood conservation strategy in anaesthesia. Br J Anaesth 2010;105:401-16. 17. Yamada T, Yamashita Y, Terai Y, Ueki M. Intraoperative blood salvage in abdominal uterine myomectomy. Int J Gynaecol Obstet 1997;56:141-5. 18. West S, Ruiz R, Parker WH. Abdominal myomectomy in women with very large uterine size. Fertil Steril 2006;85:36-9. 19. Kumakiri J, Kikuchi I, Kitade M, Matsuoka S, Kono A, Takeda S. Retrospective analysis of the efficacy of perioperative use of the cell salvage and autologous blood recovery system during laparoscopic myomectomy. Arch Gynecol Obstet 2012;285:1073-7. 20. American Medical Association. CPT 2012: Current Procedural Terminology. Chicago: American Medical Association; 2011. 21. Davies L, Brown TJ, Haynes S, Payne K, Elliott RA, McCollum C. Cost-effectiveness of cell salvage and alternative methods of minimising perioperative allogeneic blood transfusion: a systematic review and economic model. Health Technol Assess 2006;10:1-210.
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GENERAL GYNECOLOGY
Utility of cell salvage in women undergoing abdominal myomectomy Moeun Son, MD; John C. Evanko, MD; Linda B. Mongero, CCP; Sharyn N. Lewin, MD; Yu-Shiang Lu, MS; Thomas J. Herzog, MD; Jin Hee Kim, MD; Jason D. Wright, MD OBJECTIVE: We examined the use and cost of autologous blood cell salvage in women who undergo abdominal myomectomy. STUDY DESIGN: Patients who underwent abdominal myomectomy
from 2007-2011 were identified. Use of the cell salvage system and reinfusion of autologous blood in women who had the system set-up were analyzed. Cost was examined by directly reported data. RESULTS: We identified 607 patients who underwent abdominal
myomectomy. Four hundred twenty-five women (70%) had the set-up of the cell salvage system. Cell-salvaged blood was processed and reinfused into 85 of these subjects (20%). In a multivariable model, performance of myomectomy by a gynecologic-specific surgeon (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.28e3.59), >5 myomas (OR, 2.49; 95% CI, 1.27e4.89), and larger uterine size statistically were associated significantly with cell-salvage device set-up. Conversely, having a reproductive-endocrinology-infertility specialist
as the surgeon was associated with a significant reduction in cellsalvage system set-up (OR, 0.37; 95% CI, 0.21e0.66). For the women who had cell-salvage system set-up, uterine size of >15-19 weeks of gestation (OR, 3.22; 95% CI, 1.56e8.95) or 20 weeks of gestation (OR, 4.62; 95% CI, 1.45e14.73), operating time of >120 minutes (OR, 3.98; 95% CI, 1.70e9.29), and intraoperative blood loss of >1000 mL (OR, 26.31; 95% CI, 10.49e65.99) were associated significantly with a higher incidence of reinfusion of cell-salvaged blood. CONCLUSION: The routine use of cell salvage in women who undergo
abdominal myomectomy does not appear to be warranted. Cellsalvage set-up appears to be cost-effective only when reinfused, but clinical characteristics cannot predict accurately which women will require reinfusion of cell-salvaged blood. Key words: blood, cell saver, transfusion
Cite this article as: Son M, Evanko JC, Mongero LB, et al. Utility of cell salvage in women undergoing abdominal myomectomy. Am J Obstet Gynecol 2014;210:.
A
bdominal myomectomy is performed commonly for the excision of symptomatic uterine fibroid tumors in women who desire fertility preservation. Although an effective treatment, the procedure can be associated with substantial blood loss.1,2 A number of adjuvant measures are available to reduce the risk of bleeding that include preoperative administration of gonadotropinreleasing hormone agonists, placement of a pericervical tourniquet, injection of intramyometrial vasopressin, and use of
uterotonics.3-7 Despite these measures, allogeneic transfusion is often required, with reported rates between 18% and 24% in some studies.8-10 Although allogeneic red blood cell transfusion is effective in the treatment of anemia because of acute blood loss, transfusion is associated with a number of risks that include infectious complications, transfusion reactions, and a substantial cost. To limit allogeneic transfusion, cell salvage and autologous blood recovery have been developed for
From the Department of Obstetrics and Gynecology (Drs Son, Evanko, Lewin, Herzog, Kim, and Wright and Ms Lu) and Herbert Irving Comprehensive Cancer Center (Drs Lewin, Herzog, and Wright), College of Physicians and Surgeons, and Department of Clinical Perfusion, New York Presbyterian Hospital, Columbia University Medical Center (Ms Mongero), Columbia University, New York, NY. Received Nov. 25, 2013; revised Jan. 30, 2014; accepted Feb. 15, 2014. The authors report no conflict of interest. Reprints: Jason D. Wright, MD, Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, 161 Fort Washington Ave., 8th Floor, New York, NY 10032. [email protected]. 0002-9378/$36.00 ª 2014 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog.2014.02.020
procedures in which substantial blood loss is anticipated. Cell salvage has been studied for orthopedic and cardiovascular procedures, and the technology has been associated with decreased need for allogeneic blood transfusion and fewer bleeding complications.11-16 Despite the bleeding potential of myomectomy, there have been few data to describe the role of cell salvage for the procedure. Small observational studies have suggested that cell salvage may increase the postoperative hematocrit level and reduce the need for allogeneic transfusion.17-19 However, the sample size in these studies was small, and the cell-salvage system often was evaluated within a subgroup analysis and not the main focus of the studies. Furthermore, little is known about the cost-effectiveness of cell salvage for myomectomy. The primary objective of our study was to examine the usefulness of cell salvage in women who undergo abdominal myomectomy. We also investigated factors that were associated with rates of cell-salvage set-up and reinfusion and
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used these data to help estimate costs of this technology.
M ATERIALS
AND
M ETHODS
Data for women who underwent abdominal myomectomy between January 2007 and December 2011 were analyzed. A consecutive list of patients who underwent myomectomy was identified with the use of institutional databases. Patients who underwent minimally invasive, hysteroscopic, or vaginal myomectomy were excluded from the analysis, given the relatively low number of cases during the study time period. Study approval was obtained from the Columbia University Institutional Review Board. Medical records were reviewed, and relevant data were extracted. Data that were obtained included patient demographic information (age at time of surgery, race, parity), specialty of the attending surgeon, indication for surgery, preoperative imaging and laboratory data, uterine size on physical examination, total operating time, and estimated blood loss. The indication for surgery was classified based on the patient’s chief complaint. Preoperative anemia was defined as a hematocrit level of <35%. Uterine size was based on “weeks of gestation” because it is measured routinely on physical examination. Each patient was classified as to whether the cell-salvage system was set-up in the operating room before the initiation of the myomectomy. All patients who had cell-salvage use had the BRAT 2 device (COBE, Arvada, CO). This device suctions blood from the operative field, mixes it with heparinized saline solution, and stores the blood in a canister. When enough blood has been accumulated, the blood is processed by centrifugation and filtration, mixed with saline solution, and reinfused into the patient. The primary outcome for this study was the set-up of the cell-salvage device during abdominal myomectomy. The secondary outcome was incidence of reinfusion of cell-salvaged blood. We analyzed factors that potentially could be associated with cell-salvage set-up and reinfusion. We also estimated the cost of cell-salvage set-up and reinfusion
in comparison to allogeneic blood transfusion. The estimated cost of allogeneic blood transfusion was determined by the presence of a the current procedural terminology code that corresponded with each step of the blood transfusion process, including ABO (86900), Rh (86901), antibody screen (86850), immediate spin cross-match (86920), incubation technique (86921), and blood administration (36430).20 These current procedural terminology codes were then cross-referenced to Medicare reimbursement payments with the use of the website www.cms.gov. The estimated cost of the cell-salvage system was determined by the New York Presbyterian Hospital Division of Clinical Perfusion by estimation of the cost of the CellSaver (Haemonetrics, Braintree, MA) machine and supplies in addition to cost of a perfusionist’s time (both set-up/pack-up time and operating time) per hour. These estimates were used to calculate the total costs of the blood products that were used in the abdominal myomectomies that we analyzed. We performed several sensitivity analyses and estimated the total costs under a variety of clinical scenarios. Clinical scenarios included whether all of the patients who underwent abdominal myomectomy in our study had had cell-salvage device set-up, whether none of the patients had cellsalvage set-up, whether set-up was done only for those we knew were going to require reinfusion of salvaged blood, and whether only the patients we had identified as “high risk” based on our predictive indicators had cell-salvage set-up. Frequency distributions based on setup of the cell-salvage device and reinfusion of cell-salvaged blood were analyzed with c2 tests. For the analysis of reinfusion of cell-salvaged blood, we included only patients who had the cell-salvage device set-up. Multivariable logistic regression models were constructed to examine predictors of cell-salvage set-up and reinfusion of cell-salvaged blood, and adjustments were made for other demographic and clinical variables. A second predictive model for reinfusion of cell-salvaged blood that included only variables that were available before
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www.AJOG.org surgery is also reported. Results are reported as odds ratios (ORs) with 95% confidence intervals (CIs). All statistical tests were 2-sided; a probability value of < .05 was considered statistically significant. SAS software (version 9.3; SAS Institute Inc, Cary, NC) was used for all statistical analyses.
R ESULTS A total of 607 patients who underwent abdominal myomectomy were identified. In this sample, 425 patients (70.0%) had the cell salvage machine set-up for collection; 182 women (30.0%) did not. The rates of cell-salvage set-up between 2007 and 2011, per quarter, are presented in Figure 1. The procedures were performed by 46 surgeons, with a median operative volume of 6 cases (range, 1e94). The rate of cell-salvage set-up by quarter ranged from 46.4e87.8%. The clinical characteristics of the cohort are displayed in Table 1. No difference was observed between the patients who had cell-salvage system set-up and those who did not have the set-up with regard to age, race, year of surgery, or performance of previous myomectomy (P > .05 for all). Bleeding as an indication for surgery (P ¼ .01), lower preoperative hematocrit level (P ¼ .01), performance of myomectomy by a gynecologic-specific surgeon (P <.0001), uterine size >15 weeks of gestation on physical examination (P < .0001), and >5 fibroid tumors visualized on preoperative imaging (P < .0001) were associated significantly with higher incidence of cell-salvage set-up. In the adjusted model, performance of myomectomy by a gynecologic-specific surgeon (OR, 2.14; 95% CI, 1.28e3.59), >5 myomas (OR, 2.49; 95% CI, 1.27e4.89), and larger uterine size statistically were associated significantly with cell-salvage set-up (Table 1). Conversely, having a reproductive-endocrinology-infertility specialist as the surgeon was associated with a significant reduction in cellsalvage device set-up (OR, 0.37; 95% CI, 0.21e0.66). A total of 144 units of salvaged blood were processed and reinfused into 85 patients (20.0%). There were no intra-or postoperative complications that were
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General Gynecology
FIGURE 1
Cell-salvage device set-up
Rates of cell-salvage device set-up during abdominal myomectomy from 2007-2011 stratified by year and quarter. Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
associated with reinfusion of cellsalvaged blood. The rates of reinfusion of cell-salvaged blood between 2007 and 2011, per quarter, are presented in Figure 2. The women who had cell-salvage device set-up were then stratified based on whether they were reinfused, and these 2 subgroups were then compared (Table 2). Age, race, year of surgery, surgeon specialty, previous myomectomy, indication, preoperative hematocrit level, and number of fibroid tumors were not associated with reinfusion of cell-salvaged blood. Uterine size >15-19 weeks of gestation (OR, 3.22; 95% CI, 1.56e8.95) or 20 weeks of gestation (OR, 4.62; 95% CI, 1.45e14.73), operating time >120 minutes (OR, 3.98; 95% CI, 1.70e9.29), and intraoperative blood loss >1000 mL (OR, 26.31; 95% CI, 10.49e65.99) were associated significantly with a higher incidence of reinfusion of cell-salvaged blood. A predictive model that included only variables that were available before the operation and excluded operative time and blood loss revealed similar findings. Allogeneic red blood cell transfusion was also used in some patients during and after abdominal myomectomy. Allogeneic blood was transfused during surgery in 15 patients (2.5%). Three of
these patients had not had cell-salvage device set-up at the time of surgery; these patients received a total of 6 units of allogeneic packed red blood cells intraoperatively. Among the 12 patients who also had cell-salvage device set-up, they received 38 units of cell-salvaged blood and 41 units of allogeneic blood during surgery. Allogeneic blood was transfused after surgery in 41 patients (6.8%). Ten of these patients did not have cell-salvage device set-up at time of surgery; these patients received a total of 20 units of allogeneic packed red blood cells. Among the 31 patients who had also had cell-salvage device set-up in the operating room, they received 49 units of cell-salvaged blood during surgery and an additional 66 units of allogeneic blood after surgery. Of note, 6 of these patients experienced postoperative bleeding complications. Two of them required reoperation: 1 woman for hemoperitoneum and the other woman for incisional bleeding. The estimated total cost in our study, which included the cost of the cellsalvage system set-up in the 425 patients and the cost of the allogeneic blood units that were still necessary was $146,587. The estimated total costs for a variety of clinical scenarios are displayed in Table 3. The hypothesized cost for a
Research
clinical scenario in which the cell-salvage device was set up in all patients was calculated with the cost of the cellsalvage system set-up in all 607 patients and the reduced cost of the allogeneic blood units that were still required (as a crude estimate, we subtracted the 26 units of allogeneic blood that were transfused in the nonecell-salvage device set-up group in our study). Universal cell-salvage device set-up was associated with a cost of $179,819 ($33,232 more than the actual cohort). In the scenario of not setting up the cell-salvage machine in any cases, the cost was determined by conversion of the cost of each unit of reinfused cellsalvaged blood to the price of a unit of allogeneic blood, which resulted in $91,410 ($55,177 less than the actual cohort). In the ideal scenario of setting up the cell-salvage machine only in cases in which reinfusion was achieved, the estimated cost included the cost of the cell-salvage system set-up in the 85 patients who were ultimately reinfused and the cost of the allogeneic blood units that were still necessary and resulted in $67,853 ($78,734 less than the actual cohort). Finally, we hypothesized a scenario in which only the patients that we had identified as “high risk” for significant blood loss based on our multivariable analysis had had cell-salvage machine set-up; using these results, we noted a cost of $120,714 ($25,873 less than the actual cohort).
C OMMENT In an attempt to avoid allogeneic blood transfusion during the perioperative period, advances such as cell salvage have been used in gynecologic surgery without strong data to describe the effectiveness of these technologies. Although it is reassuring to have an autologous blood recovery system set-up for the possibility of significant operative blood loss, it is also associated with substantial cost. Our data demonstrated that, although the cell-salvage system may be beneficial in certain situations, its routine use in patients who undergo abdominal myomectomy might not be warranted.
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TABLE 1
Clinical and demographic characteristics stratified by set up of cellsalvage Variable
Cell-salvage No cell salvage, device set-up, n (%) n (%)
Total
425 (70.0)
Odds ratio P valuea (95% CI)b
182 (30.0)
Age at time of surgery, y
— .55
<35
123 (28.9)
57 (31.3)
Referent
35-40
193 (45.4)
74 (40.7)
1.53 (0.96e2.45)
>40
109 (25.7)
51 (28.0)
1.16 (0.69e1.96)
Race
.24
White
117 (27.5)
56 (30.7)
Referent
Black
172 (40.5)
58 (31.9)
1.34 (0.81e2.22)
Other
60 (14.1)
32 (17.6)
0.78 (0.42e1.45)
Unknown
76 (17.9)
36 (19.8)
0.86 (0.48e1.54)
2007
113 (26.6)
41 (22.5)
Referent
2008
98 (23.1)
31 (17.1)
1.15 (0.62e2.13)
2009
87 (20.5)
39 (21.4)
0.70 (0.40e1.25)
2010
62 (14.6)
43 (23.6)
0.41 (0.22e0.76)
2011
65 (15.2)
28 (15.4)
0.54 (0.28e1.03)
Year of surgery
.06
< .0001
Specialty of surgeon General obstetrics/gynecology
144 (33.9)
59 (32.4)
Referent
Gynecologic surgery
185 (43.5)
39 (21.4)
2.14 (1.28e3.59)
Gynecology oncology
12 (2.8)
11 (6.1)
0.37 (0.13e1.03)
Reproductiveendocrinology-infertility
84 (19.8)
73 (40.1)
0.37 (0.21e0.66)
Previous myomectomy
.07
No
383 (90.1)
172 (94.5)
Yes
42 (9.9)
10 (5.5)
Indication for surgery Abnormal vaginal bleeding Bulk symptoms Pelvic pain Infertility
Referent 1.82 (0.81e4.06) .01
216 (50.8)
67 (36.8)
Referent
42 (9.9)
19 (10.4)
0.60 (0.29e1.22)
102 (24.0)
58 (31.9)
0.54 (0.33e0.87)
65 (15.3)
38 (20.9)
1.01 (0.55e1.87)
Fibroid tumors on imaging, n
.0004
1-5
216 (50.8)
99 (54.4)
Referent
>5
89 (21.0)
15 (8.2)
2.49 (1.27e4.89)
120 (28.2)
68 (37.4)
0.98 (0.61e1.58)
Unknown
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
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(continued)
Cell-salvage technology has now been well-described for a number of nongynecologic procedures.11 A systematic review by Carless et al11 showed that cell salvage reduces the need for transfusions of allogeneic blood in orthopedic, cardiac, and vascular surgery. In their metaanalysis of 75 trials, they found that the use of cell salvage reduced the rate of exposure to allogeneic red blood cell transfusion by 38%. The absolute reduction in risk of receiving an allogeneic red blood cell transfusion was 21%; the use of cell salvage resulted in an average savings of 0.68 units of allogeneic red blood cells per patient (weighted mean difference, e0.68; 95% CI, e0.88 to e0.49). Earlier studies have suggested that cell salvage may be beneficial in women who undergo myomectomy.17-19 Yamada at al17 reported that the use of intraoperative cell salvage allowed surgeons to avoid allogeneic transfusion in 35 of 37 patients, which included 4 patients who had an estimated operative blood loss of >1000 mL. West et al18 found that, among 90 women, 70 women were given cell-salvaged blood (mean, 355 mL) and that allogeneic blood transfusion was necessary for only 7 women (8%). At our institution, cell-salvage technology was used liberally in women who underwent myomectomy, and we noted that autologous blood infrequently was reinfused; only 20% of those who had cell-salvage device set-up received reinfusion. Further, despite the frequent use of cell salvage, 107 additional units of allogeneic blood were still required by the cohort. The strength of this study lies in the abundance of information on confounding factors that allowed us to analyze specific variables that were associated with increased rates of set-up and use of the cell-salvage system in an effort to determine predictive clinical indicators that would be helpful before surgery. We found that, having a gynecology-specific surgeon, uterine size >15 weeks of gestation on physical examination, and >5 fibroid tumors that were seen on imaging were associated with higher rates of set-up of the cellsalvage system. However, when we
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TABLE 1
Clinical and demographic characteristics stratified by set up of cellsalvage (continued) Variable
Cell-salvage No cell device salvage, set-up, n (%) n (%)
< .0001
Uterine size on exam, wk <15
149 (35.0)
15-19 20 Unknown
91 (50.0)
Referent
130 (30.6)
34 (18.7)
2.17 (1.30e3.63)
84 (19.8)
18 (9.9)
3.27 (1.71e6.23)
62 (14.6)
39 (21.4)
1.57 (0.91e2.72)
Preoperative hematocrit level, %
a
Odds ratio P valuea (95% CI)b
.01
25-29
20 (4.7)
5 (2.8)
Referent
30-34
116 (27.3)
29 (15.9)
1.24 (0.39e3.93)
34-39
203 (47.8)
104 (57.1)
0.57 (0.19e1.72)
40
86 (20.2)
44 (24.2)
0.55 (0.17e1.77)
c2 test; b Derived from multivariable logistic regression model.
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
focused on the patients who actually received reinfusion of cell-salvaged blood, the only variable that was statistically significant and available before surgery was uterine size >15 weeks of gestation on physical examination. This association may underlie the high rates of reinfusion of cell-salvaged blood in
the study by West et al18 because only women with uterine size 16 weeks of gestation were included. Based on our data, there are few other predictive factors to help guide selective cell-salvage device set-up policies. Cell salvage is cost-effective for procedures in which the need for allogeneic
FIGURE 2
Cell-salvage reinfusion
Rates of cell salvage reinfusion during abdominal myomectomy from 2007-2011 stratified by year and quarter. Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
Research
blood transfusion is high.21 Although the cost (per unit of blood) is appreciably less for cell-salvaged blood compared with allogeneic transfusion, the overall cost-effectiveness of the cell-salvage system is dependent on the rates of reinfusion. Additionally, even if cell-salvaged blood is frequently reinfused, there can still be a need for additional allogeneic blood products. Compared with other higher risk procedures, we noted that the number of women who had cell-salvaged blood reinfused was low. Not unexpectedly, in our comparison of costs in different clinical scenarios, the estimated cost was highest for the situation in which every patient who underwent abdominal myomectomy had cell-salvage device set-up. Likewise, the estimated cost was the lowest in the ideal scenario in which we could predict accurately which patients were going to definitely receive reinfusion, and the cell-salvage device was set-up only in those patients. Use of a model to predict “high-risk” patients resulted in marginal cost-savings. These models did not account for adverse consequences of allogeneic transfusion, and clearly additional econometric studies are needed. However, our data suggest that a riskbased stratification for cell-salvage device set-up is unlikely to reduce the cost of using the technology substantially. Although our study is one of the largest to date to describe the use of the cell-salvage system for abdominal myomectomy, we acknowledge a number of important limitations. First, the study design is retrospective in nature; as such, the decision to set-up the cell-salvage system was at the discretion of the attending surgeon. However, selection bias towards using the cell-salvage system in higher risk patients likely biased our findings towards the usefulness of cell salvage, and the utility of cell salvage would have been even more limited if all women had the system set-up. Second, there are no set criteria as to when cellsalvaged blood should be reinfused. Although blood is often reinfused if enough blood cells are collected, undoubtedly a number of women received autologous blood that was of little clinical value. An abundance of literature
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TABLE 2
Characteristics of the women with reinfusion of cell-salvaged blood Variable
Reinfused, n (%)
Not reinfused, n (%)
Total
85 (20.0)
340 (80.0)
Age at time of surgery, y
P valuea
Odds ratio (95% CI)b
Predictive model odds ratio (95% CI)c
— .60
<35
28 (32.9)
95 (27.9)
35-40
35 (41.2)
158 (46.5)
0.48 (0.20e1.13)
0.60 (0.30e1.20)
>40
22 (25.9)
87 (25.6)
0.49 (0.19e1.28)
0.71 (0.33e1.55)
Race
Referent
Referent
.08
White
17 (20.0)
100 (29.4)
Black
43 (50.6)
129 (37.9)
0.70 (0.28e1.79)
1.80 (0.84e3.85)
Other
8 (9.4)
52 (15.3)
0.29 (0.06e1.28)
0.56 (0.19e1.71)
17 (20.0)
59 (17.4)
0.95 (0.32e2.86)
1.72 (0.70e4.20)
Unknown Year of surgery
Referent
Referent
.01
2007
30 (35.3)
83 (24.5)
2008
16 (18.8)
82 (24.1)
Referent 0.60 (0.21e1.67)
Referent 0.50 (0.22e1.14)
2009
8 (9.4)
79 (23.2)
0.18 (0.05e0.66)
0.22 (0.08e0.56)
2010
17 (20.0)
45 (13.2)
0.93 (0.31e2.74)
1.15 (0.49e2.71)
2011
14 (16.5)
51 (15.0)
0.75 (0.25e2.29)
0.57 (0.23e1.40)
Specialty of surgeon
.001
General obstetrics/gynecology
34 (40.0)
110 (32.4)
Gynecologic surgery
22 (25.9)
163 (47.9)
Gynecology oncology
Referent
Referent
0.47 (0.19e1.17)
0.34 (0.17e0.71)
5 (5.9)
7 (2.1)
2.81 (0.50e15.66)
1.21 (0.29e5.09)
24 (28.2)
60 (17.6)
1.25 (0.40e3.93)
1.33 (0.56e3.17)
No
68 (80.0)
315 (92.6)
Yes
17 (20.0)
25 (7.4)
Reproductive-endocrinology-infertility Previous myomectomy
.0005
Indication for surgery
Referent 1.51 (0.54e4.25)
Referent 2.82 (1.24e6.40)
.50
Abnormal vaginal bleeding
43 (50.6)
173 (50.9)
Bulk symptoms
12 (14.1)
30 (8.8)
2.12 (0.69e6.49)
1.27 (0.51e3.15)
Pelvic pain
18 (21.2)
84 (24.7)
0.81 (0.32e2.04)
0.72 (0.35e1.48)
Infertility
12 (14.1)
53 (15.6)
0.60 (0.19e1.87)
0.57 (0.23e1.44)
Fibroid tumors on imaging, n
Referent
Referent
.18
1-5
36 (42.4)
180 (52.9)
>5
19 (22.3)
70 (20.6)
Referent 1.02 (0.38e2.77)
Referent 1.27 (0.58e2.78)
Unknown
30 (35.3)
90 (26.5)
1.34 (0.53e3.38)
1.71 (0.84e3.57)
< .0001
Uterine size on examination, wk <15
8 (9.4)
141 (41.5)
15-19
27 (31.8)
103 (30.3)
Referent
Referent
3.22 (1.56e8.95)
4.71 (1.94e11.43)
20
37 (43.5)
47 (13.8)
4.62 (1.45e14.73)
15.48 (6.07e39.48)
Unknown
13 (15.3)
49 (14.4)
1.97 (0.55e7.00)
3.81 (1.34e10.83)
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
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TABLE 2
Characteristics of the women with reinfusion of cell-salvaged blood (continued) Reinfused, n (%)
Variable
Not reinfused, n (%)
P valuea
Preoperative hematocrit level, %
Predictive model odds ratio (95% CI)c
Referent
Referent
.07
25-29
6 (7.0)
14 (4.1)
30-34
26 (30.6)
90 (26.5)
1.21 (0.23e6.29)
0.88 (0.25e3.08)
35-39
44 (51.8)
159 (46.8)
1.22 (0.25e5.97)
0.72 (0.22e2.35)
40
9 (10.6)
77 (22.6)
0.70 (0.11e4.51)
0.52 (0.13e2.13)
< .0001
Operating time, min <120
13 (15.3)
197 (57.9)
120
72 (84.7)
143 (42.1)
Referent
—
3.98 (1.70e9.29)
—
< .001
Intraoperative blood loss, mL
a
Odds ratio (95% CI)b
<1000
33 (38.8)
331 (97.4)
1000
52 (61.2)
9 (2.6)
Referent
—
26.31 (10.49e65.99)
—
c test; Derived from multivariable logistic regression model; Multivariable logistic regression model including only factors available before surgery. 2
b
c
Son. Cell salvage for myomectomy. Am J Obstet Gynecol 2014.
supports the fact the young women often tolerate mild anemia well. Third, we were unable to incorporate data such as patient body mass index and medical comorbidities or surgeon level of experience and surgical volume, which
potentially could be important confounding factors. Finally, we acknowledge that our cost models are unable to incorporate a number of factors that impact cost. A priori, the goal of the cost analysis was to report descriptively the
estimated costs of cell salvage in our cohort. However, institutional costs of the technology are likely highly variable, and our model did not incorporate costs of acute and long-term complications of allogeneic transfusion, such as
TABLE 3
Cost estimates for use of cell salvage for myomectomy Cell salvage system Total cost of set-up
Total cost of perfusionist
Allogeneic blood transfusion
Setting
Cost per Cost per Red blood Cost per Total estimated Set-up, n set up, $ Time, h hour, $ Subtotal,a $ cell units, n unit,b $ Subtotal, $ cost, $
Our study results
425
125
918
54
102,697
133
330
43,890
146,587
330
35,310
179,819
133 (144d) 330
91,410
91,410
c
If all cases had cell-salvage 607 device set-up
125
1271
54
144,509
If no cases had cell-salvage — device set-up
—
—
—
—
If cell-salvage device set-up only for those who were ultimately reinfused
85
125
247
54
23,963
133
330
43,890
67,853
If cell-salvage device set-up 266 only for high-risk patients
125
756
54
76,824
133
330
43,890
120,714
a
107
Subtotal cost of cell-salvage system as determined by division of clinical perfusion by estimating the cost of the CellSaver (Haemonetrics, Braintree, MA) machine and supplies in addition to the cost of a perfusionist’s time per hour of operating time; b Determined by the presence of a current procedural terminology code that corresponded with each step of the blood transfusion process, including ABO (86900), Rh (86901), antibody screen (86850), immediate spin cross-match (86920), incubation technique (86921), blood administration (36430); c Total number of allogeneic blood units still needed, even with cell-salvage device set-up in our study; d Total number of blood units provided by the cell-salvage machine when used in our study.
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transfusion reactions and acquired blood-borne infections. In conclusion, we found that the routine use of cell-salvage technology was not beneficial in most women who undergo abdominal myomectomy. Reinfusion rates were low; allogeneic blood transfusions were often still necessary, and costs were increased. However, women with uterine size >15 weeks of gestation on physical examination were found to have significantly increased rates of reinfusion of cell-salvaged autologous blood. Further studies are needed to better elucidate other significant risk factors and to identify women who would benefit from cell-salvage technology. REFERENCES 1. Kunde K, Cortes E, Seed P, Khalaf Y. Evaluation of perioperative morbidity associated with single and multiple myomectomy. J Obstet Gynaecol 2009;29:737-41. 2. Pundir J, Krishnan N, Siozos A, et al. Perioperative morbidity associated with abdominal myomectomy for very large fibroid uteri. Eur J Obstet Gynecol Reprod Biol 2013;167:219-24. 3. Lethaby A, Vollenhoven B, Sowter M. Efficacy of pre-operative gonadotropin hormone releasing analogues for women with uterine fibroids undergoing hysterectomy or myomectomy: a systematic review. BJOG 2002;109: 1097-108. 4. Al-Shabibi N, Chapman L, Madari S, Papadimitriou A, Papalampros P, Magos A.
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